KR102453870B1 - Method And Computer Program For Deleting File Permanently - Google Patents

Abstract

The present disclosure provides a method for permanently deleting files and a computer program.
According to one aspect of the present disclosure, a deleted file is detected through real-time monitoring of a file in a file system, and a temporary file and a copy file of the temporary file are respectively created and deleted based on the information of the deleted file to permanently delete the deleted file. A method of permanently deleting files and a computer program are provided.
According to another aspect of the present disclosure, there is provided a file permanent deletion method and computer program for permanently deleting files by searching and comparing file systems in a mobile environment at regular intervals to find deleted files, and creating and deleting temporary files of deleted files. .

Description

Method And Computer Program For Deleting File Permanently

The present invention relates to a file permanent deletion method and a computer program, and more particularly, to a file permanent deletion method and a computer program for detecting a deleted file through file monitoring of a file system and permanently deleting the detected deleted file will be.

The content described in this section merely provides background information for the present embodiment and does not constitute the prior art.

Conventional data permanent deletion has been achieved by extracting deleted files from a disk, creating a deleted file table, and deleting them all at once according to a work schedule. In this way, the load of the work is concentrated on the time to process the deletion at one time according to the work schedule, which puts a load on the system, and there is a problem that the permanent deletion efficiency is lowered.

In addition, the existing method of permanently deleting data has a problem in that it is difficult to apply to a mobile environment due to a large amount of battery consumption.

Therefore, there is a need for a method for permanently deleting files that can alleviate the concentration of system load and can be applied even in a mobile environment.

Korean Patent Publication No. 10-1518483

According to one aspect of the present disclosure, a deleted file is detected through real-time monitoring of a file in a file system, and a temporary file and a copy file of the temporary file are created and deleted respectively based on the information of the deleted file to permanently delete the deleted file. Its main purpose is to provide a method for permanently deleting files and a computer program.

According to another aspect of the present disclosure, there is provided a file permanent deletion method and computer program for permanently deleting files by searching and comparing file systems in a mobile environment at regular intervals to find deleted files, and creating and deleting temporary files of deleted files. It has another main purpose.

According to an aspect of the present disclosure, there is provided a method of permanently deleting a file stored in a file system, the method comprising: setting a working environment; monitoring the existence of a deleted file in the file system; generating or updating a deleted file table by extracting deleted file information of the deleted file when there is the deleted file; generating a temporary file by extracting the deleted file information from the deleted file table; creating a copy file by copying the temporary file; deleting the temporary file and the copy file based on the working environment; and deleting the deleted file information of each of the temporary file and the copy file from the deleted file table.

According to another aspect of the present disclosure, there is provided a method for permanent deletion of a file stored in a file system, the method comprising: setting a work environment including a deletion target and a waiting time; generating a reference file table by extracting a file corresponding to the deletion target from the file system; generating a recent file table by extracting a file corresponding to the deletion target from the file system after the waiting time has elapsed; extracting deleted file information by comparing the reference file table and the recent file table, and generating a deleted file table; generating a temporary file by extracting the deleted file information from the deleted file table; deleting temporary file data that is data of the temporary file; and deleting the temporary file.

According to another aspect of the present disclosure, there is provided a computer program stored in a computer-readable recording medium in order to execute each process included in the above-described method for permanently deleting files.

According to one aspect of the present disclosure, a deleted file is detected through real-time monitoring of a file in a file system, and a temporary file and a copy file of the temporary file are created and deleted respectively based on the information of the deleted file to permanently delete the deleted file. A method for permanently deleting files may be provided.

In addition, the file permanent deletion method according to an aspect of the present disclosure has an effect of permanently deleting the deleted file so that the deleted file cannot be recovered due to the creation and deletion of the temporary file and the copy file.

In addition, when the file permanent deletion method according to an aspect of the present disclosure is applied to a mobile environment, a file system is searched and compared at regular intervals to find a deleted file, and a temporary file is created and deleted based on the information of the deleted file This prevents the workload caused by scheduling, and has the effect of permanently deleting files in a mobile environment without excessive energy consumption.

1 is a flowchart illustrating a file permanent deletion method according to an embodiment of the present disclosure.
2 is a flowchart illustrating a file permanent deletion method performed based on a permitted deletion time according to an embodiment of the present disclosure.
3 is a flowchart illustrating a file permanent deletion method performed based on a schedule time according to an embodiment of the present disclosure.
4 is a flowchart illustrating a method of permanently deleting files in a mobile environment according to an embodiment of the present disclosure.

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to exemplary drawings. It should be noted that in adding the reading reference numerals to the components of each drawing, the same components are to have the same reference numerals as much as possible even though they are displayed on different drawings. In addition, in describing the present disclosure, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present disclosure, the detailed description thereof will be omitted.

In addition, in describing the components of the present disclosure, terms such as second, first, etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, or order of the elements are not limited by the terms. Throughout the specification, when a part 'includes' or 'includes' a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated. . In addition, the '... Terms such as 'unit' and 'module' mean a unit that processes at least one function or operation, which may be implemented as hardware or software or a combination of hardware and software.

DETAILED DESCRIPTION The detailed description set forth below in conjunction with the appended drawings is intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure may be practiced.

Permanent deletion of files in the present disclosure means deleting files (preferably deleted files) stored in the file system so that they cannot be recovered.

The method of permanently deleting a file in the present disclosure is performed by creating a file by creating data having content irrelevant to the content of the deleted file in a deleted file path, and then deleting the created file. That is, in the present disclosure, unlike the existing permanent deletion method, a data generation part is additionally introduced. In addition, by performing permanent deletion through real-time monitoring of deleted files, permanent deletion is performed without a work schedule, unlike the existing permanent deletion method.

1 is a flowchart illustrating a file permanent deletion method according to an embodiment of the present disclosure.

In the file permanent deletion method according to an embodiment of the present disclosure, first, a task setting for permanent file deletion is set ( S100 ).

The working environment includes all or part of the data creation method and data deletion method for permanent deletion of files in the file system, the number of deletions, the deletion target, the deletion time (or schedule time), and temporary folder settings, but is not limited thereto. .

The data generation method is a method for generating arbitrary data, and any means that can be easily employed by a person skilled in the art is sufficient, and is not limited to a specific generation method. For example, a method of generating final data by applying a data encryption algorithm after creating data filled with random numbers in units of bits or bytes may be used. In this case, the data encryption algorithm suffices to be an algorithm that can change plain text into cipher text, and is not limited to a specific algorithm.

The data deletion method is a method of erasing existing data so that it cannot be recovered by overwriting data with other data. It is sufficient as long as it is a method that can be easily employed by a person skilled in the art, and is not limited to a specific deletion method. does not For example, the data deletion method may be a method of performing a specific data deletion algorithm a predetermined number of times. As such a data deletion algorithm, DoD 5220.22-M or Zero-Fill may be used. DoD 5220.22-M overwrites the data area three times, once with specific data, once with its complement, and once randomly. Zerofill is to change all data to 0 bits. Such a data deletion algorithm suffices as long as the data in the data area can be overwritten, and is not limited to a specific algorithm. The more the data deletion algorithm is performed, the lower the probability of data recovery.

The deletion target is set to permanently delete only a specific file. Accordingly, a specific file or a specific path may be set as a deletion target, and a specific file and a file excluding a specific path may be set as a deletion target. For example, only Microsoft Office files can be permanently deleted by setting only files with extensions of DOC, DOCX, PPT, PPTX, XLS, or XLSX to be deleted.

The allowable deletion time and the schedule time will be described later in detail with reference to FIGS. 2 and 3 , respectively.

The temporary folder (temporary folder or Temp) is a folder for copying temporary files as needed and storing the copy files. It is preferable that such a temporary folder exists in the same partition as the deleted file. Usually, one physical storage device (storage, for example, a disk drive) is divided into multiple logical partitions, so it is efficient to create a temporary folder in each logical partition as well. The temporary folder setting may be information such as a creation method of a temporary folder in the file system, for example, a creation location, size, attribute information (eg, permission setting, etc.).

When the working environment is set, it is monitored whether a file to be deleted occurs in the file system (S110).

The method of monitoring a deleted file in real time may be performed by calling a file monitoring function provided by the operating system. Through the file monitoring function, file attribute information such as file creation, change, deletion, and name change can be monitored.

If a deleted file is detected during step S110, it goes to step S130, otherwise, monitoring of the deleted file is continued (S120). In this case, if the file permanent deletion method according to an embodiment of the present disclosure is implemented based on a thread, S110 may be continuously performed even when step S130 is performed.

When a deleted file is detected, deleted file information is extracted from the deleted file to create or update a deleted file table (S130). Here, creation or update means to create a deleted file table when the deleted file table is not created, to create an entry based on the deleted file information, and to add it to the deleted file table.

At this time, the deleted file information includes the name, path, and time information of the deleted file. The time information includes the deletion time of the file, and may further include information on the size and creation time of the deleted file. For example, when a deleted file is moved to the recycle bin depending on the operating system, detailed information such as the size of the deleted file may be retrieved, but otherwise, the corresponding information may not be retrieved.

If a large number of deleted files occur in a short time, the permanent deletion operation may be accumulated and delayed. At this time, the deleted file table acts like a cache.

When the deleted file table is created or updated, the deleted file information stored in the deleted file table is sequentially fetched and a temporary file is created according to the data generation method set in the work environment (when the data generation method is set) (S140). In this case, the attribute of the temporary file is based on the deleted file data, and the data of the temporary file is different from the data of the deleted file corresponding to the deleted file data. The data of the temporary file may be encrypted data filled with bit or byte random numbers, as described above.

When the file size information is not included in the deleted file information, which is the basis for creating such a temporary file, a temporary file of a predetermined specific size or an arbitrarily determined size may be created.

In order to lower the recovery probability of a deleted file, a temporary file may be created with the same name as the deleted file, but with a different file size.

It is determined whether a temporary file is created (S150). If the temporary file is not created, the deleted file information is added to the deleted file table again to update the deleted file table, and the process is performed again from S130.

Temporary file creation fails when write-protection rights (eg Read-Only right) are set on the deleted file. In this case, it is necessary to delay the permanent deletion for a while until the write-protection permission is released. Accordingly, the deleted file information is added to the deleted file table again.

If the write-protect permission is not released, permanent deletion cannot proceed any more, so either delete the deleted file information from the deleted file table or add the deleted file information to the deleted file table, but use the allowable deletion time set in the working environment. Therefore, it is possible not to proceed with the subsequent procedure for the deleted file information. This will be described later in detail with reference to FIG. 2 .

When the temporary file is created, a copy file of the temporary file is created (S160).

The reason for creating a copy file is to additionally perform permanent deletion up to the slack space of the drive.

Thereafter, the temporary file and the copy file respectively created in S140 and S160 are deleted (S170), and deleted file information of the corresponding temporary file and the copy file is deleted from the deletion file table (S180).

Step S110 according to an embodiment of the present disclosure may be continuously performed without interruption even when other steps are being performed. In this case, when the temporary file and the copy file are deleted in step S170, the corresponding deleted file is detected in real time, and the file deletion information is added to the deleted file table again. Accordingly, unnecessary deleted file information should be deleted from the deleted file table through step S180.

When deleting temporary files and copy files, the recovery probability can be lowered by changing the name and/or size of the files differently and then deleting them.

2 is a flowchart illustrating a method of permanently deleting a file based on a permitted deletion time according to an embodiment of the present disclosure.

In order to perform permanent file deletion based on the allowable deletion time, a work environment including the allowable deletion time is set (S200). In step S200, as described above, a data generation method, a data deletion method, a deletion target, a temporary folder setting, and the like may be further set. In FIG. 2, it is assumed that not only the deletion permitted time but also the data creation method, the data deletion method, the deletion target and the temporary folder setting (environment setting) are set in the work environment setting.

The allowable deletion time is set in order to perform permanent deletion of the detected deleted file only within the period of time within the allowable deletion time from the detection of the deleted file. According to an embodiment of the present disclosure, permanent deletion of a deleted file is performed based on deleted file information stored in the deleted file table. When permanent deletion fails, information on the failed file is added to the deleted file table again. have. Therefore, when the allowable time for deletion has elapsed from the time when the deletion file is detected by setting the allowable time for deletion, the permanent deletion process is no longer performed. For example, if the allowable deletion time is set to 10 seconds, after 10 seconds have elapsed after the detection of the deleted file, permanent deletion of the corresponding deleted file information is not performed any more.

When the working environment is set, the existence of the deleted file in the file system is monitored (S210). If a deleted file is detected during step S210, the process proceeds to step S230, otherwise, monitoring of the deleted file is continued (S220).

When a deleted file is detected, the deleted file table is created or updated by extracting the deleted file information from the deleted file only when the corresponding deleted file is included in the deletion target set in the working environment (S230).

If the deleted file table has been created or updated and the current time is within the allowable time for deletion, the deleted file information stored in the deleted file table is retrieved and the corresponding deleted file (or deleted file information) is retrieved according to the data creation method set in the working environment A temporary file is created (S240). In this case, the temporary file may have the same name as the deleted file, but the file size of the file may be different.

Next, it is determined whether the temporary file is created in S240 (S250). If the temporary file is not created, the corresponding deleted file information is added to the deleted file table again, and a retry is made from step S230.

If the temporary file is successfully created in S240, a copy of the temporary file is created in the temporary folder created based on the temporary folder setting (S260).

Thereafter, the data of the temporary file created in step S240 is deleted according to the data deletion method set in the work environment (S270).

In step S270, the required time varies depending on which data deletion algorithm is selected as the data deletion method. This required time increases in proportion to the number of times the data deletion algorithm is performed.

Finally, the temporary file and the copy file created in S240 and S260 are deleted respectively (S280), and deleted file information of the corresponding temporary file and the copy file is deleted from the deleted file table (S290). Such deletion may be performed after changing the names and sizes of the temporary file and the copy file differently, as described above.

3 is a flowchart illustrating a method for permanently deleting files based on a schedule time according to an embodiment of the present disclosure.

In order to perform permanent file deletion based on a schedule time, a work environment including a time allowed for deletion is set ( S300 ). In step S300, as described above, a data generation method, a data deletion method, a deletion target, a temporary folder setting, and the like may be further set. In FIG. 3, it is assumed that not only the schedule time but also the data generation method, the data deletion method, the deletion target, and the temporary folder setting (environment setting) are set in the work environment setting.

The schedule time is the time set to permanently delete the deleted files detected through the monitoring of the file system. For example, if the schedule time is set to 12:00 noon every day, the deleted files are permanently deleted at 12:00 noon every day.

When the working environment is set, it is monitored whether a file to be deleted occurs in the file system (S310). If a deleted file is detected during step S310, the process goes to step S330, otherwise, monitoring of the deleted file is continued (S320).

When a deleted file is detected, deleted file information is extracted from the corresponding deleted file to create or update a deleted file table (S330).

Thereafter, the deleted file information stored in the deleted file table is fetched and a temporary file corresponding to the deleted file (or deleted file information) is generated according to the data generation method set in the working environment (S340). In this case, the temporary file may have the same name as the deleted file, but the file size may be different.

Next, it is determined whether the set schedule time has come (S350). If the schedule time has come, it goes to step S360, otherwise, real-time monitoring of the deleted file in step S310 is continued.

If it corresponds to the schedule time, the monitoring of step S310 is stopped, and a copy file is created for all temporary files created in the temporary folder, respectively (S360). At this time, each copy file has the same name as the name of the deleted file corresponding to each temporary file, and is created in the same path as the path of the deleted file. The names and paths of these deleted files are included in the deleted file information stored in the deleted file table.

After the copy file is created, the data of the copy file is deleted according to the data deletion method set in the working environment (S370).

Thereafter, the temporary file and the copy file respectively created in steps S340 and S360 are deleted (S380). In addition, the deleted temporary file and the deleted file information of the copy file are deleted from the deleted file table, and the monitoring of the stopped step S310 is resumed (S390).

When deleting the temporary file and the copy file in S190, changing the name and size of the file differently and then deleting the file is advantageous to lower the recovery probability. Such deletion may be performed after changing the names and sizes of temporary files and copy files, as described above.

4 is a flowchart illustrating a method of permanently deleting files in a mobile environment according to an embodiment of the present disclosure.

In the embodiment of Fig. 4, a temporary folder is used as a place for creating a temporary file, not for storing a copy file. To permanently delete a deleted file, a temporary file must be created in the original path of the deleted file. do. In this case, in the file permanent deletion method according to an embodiment of the present disclosure, a temporary file is created in a temporary folder.

In order to perform permanent file deletion without overloading of work and using excessive energy even in a mobile environment, in the embodiment of FIG. 4, the file system is searched for a period of waiting time corresponding to a specific time, rather than monitoring the file system in real time. use the method The waiting time is the time to wait until the next operation (step) of permanent deletion is performed. For example, if the waiting time is set to 3 hours, the latest file table is created 3 hours after the reference file table is created.

A work environment including the waiting time is set (S400). In step S400, as described above, a data generation method, a data deletion method, a deletion target, a temporary folder setting, and the like may be further set. In FIG. 4 , it is assumed that not only the waiting time but also the data generation method, the data deletion method, the deletion target and the temporary folder setting (environment setting) are set in the work environment setting.

In FIG. 4, two file system searches are used to detect a deleted file to be permanently deleted. The first file system search is to create a reference file table, and the second file system search is to create a recent file table. Deleted files are found by comparing each file table. At this time, the first file system search and the second file system search are performed with a certain time interval (waiting time).

When the working environment is set, all files corresponding to the set deletion target are searched in the file system, and file information is extracted from the searched files to generate a reference file table (S410).

After the reference file table is created, it waits until the waiting time elapses (S420).

Since the waiting time has elapsed, all files corresponding to the deletion target are searched again in the file system, file information is extracted, and a recent file table is created (S430).

Thereafter, the deleted file information is extracted by comparing the reference file table with the recent file table, and a deleted file table is generated (S440). As a method of extracting deleted file information, a method of extracting a file in the reference file table but not in the recent file table as a deleted file may be used, but is not limited thereto. The deleted file information included in the deleted file table preferably includes the name, path, size, and creation and deletion time of the deleted file.

The deleted file information stored in the created deleted file table is sequentially fetched, and a temporary file corresponding to each deleted file is generated according to the data generation method set in the working environment (S450). If the temporary file is not created in the path of the deleted file information, the temporary file is created in the created temporary folder based on the temporary folder setting set in the working environment. Temporary file data is created according to the data creation method set in the working environment. In this case, the temporary file may have the same name as the deleted file, but the file size may be different.

Thereafter, the data of the temporary file is deleted according to the data deletion method set in the work environment (S460).

Finally, the temporary file is deleted (S470). Such deletion can be performed after changing the name and size of the temporary file differently, as described above.

When all steps up to step S470 are completed, it is preferable to return to step S410 to permanently delete the permanently deleted file and perform the permanent deletion process again.

Although it is described that each process is sequentially executed in FIGS. 1 to 4 , this is merely illustrative of the technical idea of an embodiment of the present disclosure. In other words, one of ordinary skill in the art to which an embodiment of the present disclosure pertains may change the order described in FIGS. Since the above process can be variously modified and modified by executing the above process in parallel, it is not limited to the time-series sequence of FIGS. 1 to 4 .

Various implementations of each process, step, algorithm, and file table described herein may include a digital electronic circuit, an integrated circuit, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), computer hardware, firmware, software, and/or combinations thereof. These various implementations may include being implemented in one or more computer programs executable on a programmable system. The programmable system includes at least one programmable processor (which may be a special purpose processor) coupled to receive data and instructions from, and transmit data and instructions to, a storage system, at least one input device, and at least one output device. or may be a general-purpose processor). Computer programs (also known as programs, software, software applications or code) contain instructions for a programmable processor and are stored on a "computer-readable recording medium".

The computer-readable recording medium includes all types of recording devices in which data readable by a computer system is stored. These computer-readable recording media are non-volatile or non-transitory, such as ROM, CD-ROM, magnetic tape, floppy disk, memory card, hard disk, magneto-optical disk, and storage device. It may further include a medium or a transitory medium such as a data transmission medium. In addition, the computer-readable 　 recording medium may be distributed in a network-connected computer system, and the computer-readable code may be stored and executed in a distributed manner.

Various implementations of the systems and techniques described herein may be implemented by a programmable computer. Here, the computer includes a programmable processor, a data storage system (including volatile memory, non-volatile memory, or other types of storage systems or combinations thereof), and at least one communication interface. For example, the programmable computer may be one of a server, a network appliance, a set-top box, an embedded device, a computer expansion module, a personal computer, a laptop, a Personal Data Assistant (PDA), a cloud computing system, or a mobile device.

The above description is merely illustrative of the technical idea of this embodiment, and various modifications and variations will be possible without departing from the essential characteristics of the present embodiment by those of ordinary skill in the art to which this embodiment belongs. Accordingly, the present embodiments are intended to explain rather than limit the technical spirit of the present embodiment, and the scope of the technical spirit of the present embodiment is not limited by these embodiments. The protection scope of this embodiment should be interpreted by the claims below, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present embodiment.

Claims (19)

In a method for permanent deletion of a file stored in a file system performed in a system running a program in a PC environment,
the process of setting up a working environment;
monitoring the existence of a deleted file in the file system;
generating or updating a deleted file table by extracting deleted file information of the deleted file when there is the deleted file;
generating a temporary file by extracting the deleted file information from the deleted file table;
creating a copy file by copying the temporary file;
deleting the temporary file and the copy file based on the working environment; and
Deleting the deleted file information of each of the temporary file and the copy file from the deleted file table,
The process of creating the copy file includes creating the copy file by copying the temporary file to a temporary folder created based on the working environment. According to claim 1,
The work environment is a method for permanently deleting files, characterized in that it includes a data creation method, a data deletion method, a deletion target and a temporary folder setting method. 3. The method of claim 2,
Data generation according to the data generation method,
A method of permanently deleting a file, characterized in that it is performed by generating and encrypting data filled with bit or byte random numbers. 3. The method of claim 2,
The work environment further includes a time allowed for deletion,
The process of creating the temporary file is,
The method of permanently deleting files, characterized in that the temporary file is created only within the allowable time for deletion. The method of claim 1,
After the process of creating the copy file, the process of deleting temporary file data that is data of the temporary file
File permanent deletion method, characterized in that it further comprises. 6. The method of claim 5,
Data deletion according to the data deletion method,
The data deletion algorithm is performed a preset number of times,
The process of deleting the temporary file data is,
The file permanent deletion method, characterized in that the temporary file data is deleted using the data deletion method. 3. The method of claim 2,
The work environment further includes a schedule time,
The process of creating the temporary file is,
The method of permanently deleting files, characterized in that the temporary file is created in a temporary folder created based on the temporary folder setting method. 8. The method of claim 7,
When the schedule time is reached, the monitoring process is stopped,
The process of creating the copy file is:
In the one or more temporary files included in the temporary folder, each of the deleted file information is extracted from the deleted file table, and the copy files corresponding to the one or more temporary files are respectively created. . 9. The method of claim 8,
The deleted file information includes a name and a path of the deleted file,
The process of creating the copy file is:
File permanent deletion method, characterized in that the copy file is created with the same name and path as the deleted file. 10. The method of claim 9,
After the process of creating the copy file, the process of deleting the copy file data that is the data of the copy file
File permanent deletion method, characterized in that it further comprises. 11. The method of claim 10,
Data deletion according to the data deletion method,
The data deletion algorithm is performed a preset number of times,
The process of deleting the copy file data is,
The file permanent deletion method, characterized in that the copy file data is deleted using the data deletion method. 12. The method of claim 11,
After the process of deleting the deleted file information, the file permanent deletion method, characterized in that the monitoring process is resumed. According to claim 1,
The process of creating the temporary file is,
Permanent file, characterized in that based on the name and size information of the deleted file included in the deleted file information, a temporary file having the same name and name but a different file size from the size of the deleted file is created. How to delete. According to claim 1,
The process of deleting the temporary file and the copy file is,
A file permanent deletion method, characterized in that the temporary file and the copy file are deleted by changing the name and size of each. In a method for permanent deletion of a file stored in a file system performed in a system running a program in a mobile environment,
The process of setting a work environment including a deletion target and a waiting time;
generating a reference file table by extracting a file corresponding to the deletion target from the file system;
generating a recent file table by extracting a file corresponding to the deletion target from the file system after the waiting time has elapsed;
extracting deleted file information by comparing the reference file table and the recent file table, and generating a deleted file table;
generating a temporary file by extracting the deleted file information from the deleted file table;
deleting temporary file data that is data of the temporary file; and
Including the process of deleting the temporary file,
In the process of creating the temporary file, based on the name and size information of the deleted file included in the deleted file information, the name and name of the deleted file are the same, but the file size is different from the size of the deleted file. File permanent deletion method, characterized in that to create a. 16. The method of claim 15,
The process of deleting the temporary file is:
File permanent deletion method, characterized in that the deletion by changing the name and size of the temporary file. A computer program stored in a computer-readable recording medium to execute each process included in the method for permanently deleting files according to any one of claims 1 to 16.

delete delete

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